#pragma once

#include <string>

namespace ahttpd 
{
class Base64 
{
private:
    const static std::string base64_chars;

    /**
     * \brief Test whether a character is a valid base64 character
     * \param c The character to test
     * \return true if c is a valid base64 character
     */
    static bool is_base64(unsigned char c) 
    {
        return (c == 43 || // +
               (c >= 47 && c <= 57) || // /-9
                (c >= 65 && c <= 90) || // A-Z
                      (c >= 97 && c <= 122)); // a-z
    }
public:

    /**
     * \brief Encode a char buffer into a base64 string
     * \param input The input data
     * \param len The length of input in bytes
     * \return A base64 encoded string representing input
     */
    static std::string encode(unsigned char const * input, size_t len) 
    {
        std::string ret;
        int i = 0;
        int j = 0;
        unsigned char char_array_3[3];
        unsigned char char_array_4[4];

        while(len--) 
        {
            char_array_3[i++] = *(input++);
            if(i == 3) 
            {
                char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
                char_array_4[1] = ((char_array_3[0] & 0x03) << 4) +
                    ((char_array_3[1] & 0xf0) >> 4);
                char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) +
                    ((char_array_3[2] & 0xc0) >> 6);
                char_array_4[3] = char_array_3[2] & 0x3f;

                for(i = 0; (i <4) ; i++)
                    ret += base64_chars[char_array_4[i]];
                        i = 0;
            }
            }

        if(i) 
        {
            for(j = i; j < 3; j++)
                char_array_3[j] = '\0';

            char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
            char_array_4[1] = ((char_array_3[0] & 0x03) << 4) +
                ((char_array_3[1] & 0xf0) >> 4);
            char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) +
                ((char_array_3[2] & 0xc0) >> 6);
            char_array_4[3] = char_array_3[2] & 0x3f;
    
            for(j = 0; (j < i + 1); j++)
                ret += base64_chars[char_array_4[j]];
    
            while((i++ < 3))
                ret += '=';
        }

        return ret;
    }

    /**
     * \brief Encode a string into a base64 string
     * \param input The input data
     * \return A base64 encoded string representing input
     */
    static std::string encode(std::string const & input) 
    {
        return encode(reinterpret_cast<const unsigned char *>(input.data()), input.size());
    }

    /**
     * \brief Decode a base64 encoded string into a string of raw bytes
     * \param input The base64 encoded input data
     * \return A string representing the decoded raw bytes
     */
    static std::string decode(std::string const & input) 
    {
        size_t in_len = input.size();
        int i = 0;
        int j = 0;
        int in_ = 0;
        unsigned char char_array_4[4], char_array_3[3];
        std::string ret;

         while(in_len-- && ( input[in_] != '=') && is_base64(input[in_])) 
        {
            char_array_4[i++] = input[in_]; in_++;
            if(i ==4) 
            {
                for(i = 0; i <4; i++) 
                {
                    char_array_4[i] = 
                        static_cast<unsigned char>(base64_chars.find(char_array_4[i]));
                }
                        char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
                        char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
                        char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];

                        for (i = 0; (i < 3); i++)
                            ret += char_array_3[i];
                        i = 0;
            }
        }

        if(i) 
        {
            for(j = i; j <4; j++)
                char_array_4[j] = 0;

            for(j = 0; j <4; j++) 
            {
                char_array_4[j] = 
                    static_cast<unsigned char>(base64_chars.find(char_array_4[j]));
            }
            char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
            char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
            char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];

            for(j = 0; (j < i - 1); j++)
                ret += static_cast<std::string::value_type>(char_array_3[j]);
        }

        return ret;
    }
};

}    /**< namespace ahttpd */
